Dimanganese trioxide

Toxicity to reproduction

Administrative data

Endpoint:

reproductive toxicity, other

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

publication

Title:

Effect of the dietary manganese level on tissue manganese, iron, copper and zinc concentrations in female rats and their fetuses

Author:

Järvinen R., Ahlström A.

Year:

1975

Bibliographic source:

Medical Biology 53: 93 - 99

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Principle of test: Oral administration of manganese sulphate heptahydrate to pregnant rats to a final concentration of manganese of 24, 54, 154, 504 or 1004 mg/kg dry diet (estimated mg/kg body weight: 2, 5, 13, 42, 84 mg/kg bw). The animals were mated and the offspring collected by caesarean section at day 21 of pregnancy.
- Parameters analysed / observed: The number of implantation sites, resorptions and fetuses were recorded. The fetuses were weighed and observations made. In addition, the manganese, iron, copper and zinc concentrations in the fetal body and in the liver of pregnant and non-pregnant (control) animals were determined.

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

manganese(2+);sulfate;heptahydrate

Cas Number:

13492-24-5

Molecular formula:

H14MnO11S

IUPAC Name:

manganese(2+);sulfate;heptahydrate

Specific details on test material used for the study:

- Name of the test material (as cited in the publication): Manganese sulphate
- Molecular formula: MnSO4 x 7 H2O (manganese sulphate heptahydrate; CAS no.: 13492-24-5)

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Orion Yhtymä Oy, Ylä-Mankkaa Farm, Mankkaa, Finland
- Housing: Animals were housed individual wire bottom stainless steel cages.
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 24
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: feed

Remarks on MMAD:

N.A.

Vehicle:

unchanged (no vehicle)

Details on exposure:

DIET PREPARATION: The experimental diet was prepared by adding to the salt mixture suitable quantities of the test item to make the manganese levels of the finished diet 24, 54, 154, 504 and 1004 mg / kg dry diet. The experimental diets were prepared in 15 kg portions in a Hobart mixer and stored in plastic containers at - 10 °C.

Details on mating procedure:

- M/F ratio per cage: 1:3
- Length of cohabitation: Overnight
- Proof of pregnancy: The day on which spermatozoa was found in the vaginal smear was referred to as day 0 of pregnancy

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

N.A.

Duration of treatment / exposure:

Administration of manganese sulphate heptahydrate for eight weeks prior to mating and during pregnancy (approx. 11 weeks in total)

Frequency of treatment:

daily; ad libitum

Details on study schedule:

N.A.

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

4 other: mg Mn / m3

Remarks:

Basis: nominal in diet

Doses / concentrations 2

Dose / conc.:

24 other: mg Mn / m3

Remarks:

Basis: nominal in diet

Doses / concentrations 3

Dose / conc.:

54 other: mg Mn / m3

Remarks:

Basis: nominal in diet

Doses / concentrations 4

Dose / conc.:

154 other: mg Mn / m3

Remarks:

Basis: nominal in diet

Doses / concentrations 5

Dose / conc.:

504 other: mg Mn / m3

Remarks:

Basis: nominal in diet

Doses / concentrations 6

Dose / conc.:

1 004 other: mg Mn / m3

Remarks:

Basis: nominal in diet

No. of animals per sex per dose:

17 females per dose group

Control animals:

yes, plain diet

Details on study design:

N.A.

Positive control:

N.A.

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: No data

DETAILED CLINICAL OBSERVATIONS: No data

BODY WEIGHT: Yes
- Time schedule for examinations: On gestation day 0 (day of fertilization) and 21

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes / No / No data
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes / No / No data

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No data

OTHER: Blood samples were taken for hematological examination on day 21

Oestrous cyclicity (parental animals):

No data

Sperm parameters (parental animals):

No data

Litter observations:

Fetuses were weighed individually and stored at -20 °C
Five fetuses taken at random from each group and after fixing 70% ethanol alizarin-stained bone specimens were prepared from them.
PARAMETERS EXAMINED
The following parameters were examined in offspring:
- external examinations: weighed, examination for gross malformations
- Skeletal examination
- other: Determination of Mn, Fe, Cu and Zn concentration in body

Postmortem examinations (parental animals):

SACRIFICE
- Maternal animals: All surviving animals at day 21

GROSS NECROPSY
- Fetuses were weighed individually and analysed

HISTOPATHOLOGY / ORGAN WEIGHTS
- Hemoglobin determined from blood samples taken at day 21.
- Maternal livers were weighed on necropsy

OTHER: Thirty fetuses taken at random from each group were analysed for the dry matter content and 8 - 10 randomly selected fetuses from each group were analysed for the ash content. Pooled samples of two fetuses from each litter were used for mineral analyses.

Statistics:

Arithmetic means and standard errors were calculated. The significance of differences between the experimental groups was tested by the Student's t-test.

Reproductive indices:

N.A.

Offspring viability indices:

N.A.

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

not specified

Dermal irritation (if dermal study):

not examined

Mortality:

not specified

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

Pregnant females fed high manganese diets showed a slight tendency to lower blood hemoglobin values: the hemoglobin concentration was significantly lower in the high dose group (1004 mg Mn/kg diet)

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Other effects:

effects observed, treatment-related

Description (incidence and severity):

The livers showed no diet induced differences in size or dry matter content. The liver Mn level was higher in the pregnant than in the non-pregnant females and increased as more Mn was added to the pregnant animal's diet. In the case of non-pregnant females the Mn intake had no particular effect on the liver Mn concentration, whereas the liver iron content decreased as a function of the dietary Mn level. The liver copper concentration of pregnant females tended to be higher in the groups receiving the largest doses of Mn but the effect was not seen in the non-pregnant groups. The zinc content of the liver was not affected by the dietary Mn level or by pregnancy.
The fetal iron concentrations decreased with the increasing dietary Mn intake of the dam. The same holds true for the copper content.
The highest zinc concentration was found in the fetuses of dams fed the largest amount of Mn.

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

not examined

Reproductive performance:

no effects observed

Description (incidence and severity):

The fetal body weights and the dry matter and ash contents were nearly the same in all the experimental groups with the exception of Group V, in which the fetal weight was lower then in the other groups.

Effect levels (P0)

Dose descriptor:

NOAEL

Effect level:

1 004 mg/kg diet

Based on:

test mat.

Sex:

female

Basis for effect level:

other: no adverse effects observed

Target system / organ toxicity (P0)

Critical effects observed:

not specified

Results: P1 (second parental generation)

General toxicity (P1)

Clinical signs:

not examined

Dermal irritation (if dermal study):

not examined

Mortality:

not examined

Body weight and weight changes:

not examined

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

not examined

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Other effects:

not examined

Reproductive function / performance (P1)

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

not examined

Reproductive performance:

not examined

Effect levels (P1)

Remarks on result:

not measured/tested

Target system / organ toxicity (P1)

Critical effects observed:

not specified

Results: F1 generation

General toxicity (F1)

Clinical signs:

not examined

Dermal irritation (if dermal study):

not examined

Mortality / viability:

not specified

Body weight and weight changes:

effects observed, non-treatment-related

Description (incidence and severity):

Fetal body weight was slightly decreased (9%) in animals of the 504 mg Mn/kg dose group.

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Histopathological findings:

not examined

Other effects:

effects observed, treatment-related

Description (incidence and severity):

The fetal iron concentrations decreased with the increasing dietary manganese intake of the dam. The same appeared to hold true to some extent of the fetal copper content, although no significant differences were seen between the groups. The highest zinc concentration was found in the fetuses of dams fed the largest amount of manganese.

Developmental neurotoxicity (F1)

Behaviour (functional findings):

not examined

Developmental immunotoxicity (F1)

Developmental immunotoxicity:

not examined

Details on results (F1)

The test material did not cause gross malformations or bone structure anomalises. Fetal weight was also not affected.

Effect levels (F1)

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

1 004 mg/kg diet

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no adverse effects observed

Target system / organ toxicity (F1)

Critical effects observed:

not specified

Results: F2 generation

General toxicity (F2)

Clinical signs:

not examined

Dermal irritation (if dermal study):

not examined

Mortality / viability:

not examined

Body weight and weight changes:

not examined

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

not examined

Histopathological findings:

not examined

Other effects:

not examined

Developmental neurotoxicity (F2)

Behaviour (functional findings):

not examined

Developmental immunotoxicity (F2)

Developmental immunotoxicity:

not examined

Effect levels (F2)

Remarks on result:

not measured/tested

Target system / organ toxicity (F2)

Critical effects observed:

not specified

Overall reproductive toxicity

Reproductive effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

In this study, no impact of manganese sulphate heptahydrate on reproductive parameters and no impact on fetuses were observed. Thus, the NOAEL for maternal rats and the fetuses was 1004 mg/kg diet, which is equal to 84 mg/kg body weight.

Executive summary:

In a reproductive toxicity study, manganese sulphate heptahydrate was administered to 17 female Sprague Dawley rats per group (6 groups) for 8 weeks and during pregnancy by feed. After 8 weeks, the animals were allowed to mate. On gestation day 21 the animals were sacrificed, the uterus removed and the number of fetuses, implantation sites and resorptions were determined. The fetuses were subjected to skeletal staining and the concentrations of manganese, Fe, Cu and Zn were determined in both whole fetus and maternal liver. There was no impact on fetuses at any of the doses studied. There was also no impact on reproductive parameters at any dose level. The manganese content was highest in the fetus of dams given the highest amounts of manganese. Based on these results, the NOAEL for maternal rats and the fetuses was 1004 mg/kg diet which is equal to 84 mg/kg body weight.

This information is used in a read-across approach in the assessment of the target substance. 

For justification of read-across please refer to the attached read-across statement (see IUCLID section 13).